Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 66b6c03f8bd38f42…

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: 4c52dd8a7bd13ed2f3c83c38771fa527 SHA-1: 20ac1c34bf0aaec6f44d61baa09a9d75e2256e38 SHA-256: 66b6c03f8bd38f425e605323c2ee02ac111f6f4b49c992fbbe8ec92bd547b591
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1047 WMI

The presence of a Workbook_Open macro and CreateObject calls strongly indicates malicious VBA code execution. The macro attempts to execute obfuscated commands, including writing a batch file to 'c:\programdata\jledshf.bat' and a VBScript to 'c:\programdata\sduoixo.vbs', and also attempts to download payloads from multiple URLs. This suggests the primary purpose is to download and execute a second-stage payload.

Heuristics 6

  • ClamAV: Doc.Malware.Valyria-10004384-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10004384-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
527d0656a0c2c323955d068683ef8f7e20c035cda247a1e24383595c0eb3403b		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 7821 bytes
vbaProject_00.bin
8656e78d558095720421e77aef39752a594b6e856d6b71f528a88968ddcc31f7		 vba-project OOXML VBA project: xl/vbaProject.bin 37888 bytes
Detection
ClamAV: Doc.Malware.Valyria-10004384-0
Obfuscation or payload: unlikely

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